https://dlaa.me/markdownlint/#%25m!%5BThe%20default%2C%20focused%2C%20and%20disabled%20%3Ctextarea%3E%20element%20in%20Firefox%2071%20and%20Safari%2013%20on%20Mac%20OSX%20and%20Edge%2018%2C%20Yandex%2014%2C%20Firefox%20and%20Chrome%20on%20Windows%2010.%5D(textarea_basic.png)
Since the alt tag doesn't get parsed as HTML, there shouldn't be a need to escape these.
Ran into this because i had been escaping the tags, but then running prettier would clean off the escaping because it was not needed.

Similar thing happens with link title strings, but that's probably a separate bug